This invention relates generally to internal combustion engines and, more particularly, to internal combustion engines for portable power generating equipment.
Portable power generating equipment typically consists of an internal combustion engine coupled to an electrical generator or alternator. Typically, general purpose internal combustion engines are used in portable power generating equipment. Such service however imposes a number of peculiar requirements on the engines that are so used. Accordingly, it is desireable to design engines specifically for use in portable power generators.
Two important design criteria are engine size and weight. The versatility, and hence the overall value, of a portable power generator is improved by reducing its size and weight. Because the engine makes up a significant portion of the overall size and weight of the generator, significant improvement can be realized by reducing the size and weight of the engine.
Another important design criterion is speed control. In prior generators, wherein the engine ran at a fixed constant speed in order to provide a desired constant output frequency, precise speed control, except at the desired constant speed, was relatively unimportant. In more recent designs, such as that shown for example in the co-pending application Ser. No. 897,380, filed Jun. 11, 1992, of Kern, et al. entitled "Engine-Driven Generator," the specification of which is incorporated by reference herein, the output frequency is independent of engine speed, and engine speed is determined by an electronic control. This requires that precise speed control be available over the entire range of engine speeds. In the past, it has been difficult to achieve precise speed control at low speeds where a small change in throttle position results in a large change in engine speed.
Still another design criterion is economy. As noted, the engine makes up a significant portion of a portable power generator and reflects a significant portion of its overall cost. Engines that can be economically manufactured and operated are favored.
In view of the foregoing, it is a general object of the present invention to provide a new and improved internal combustion engine for power generating equipment.
It is a further object of the present invention to provide a new and improved internal combustion engine that provides precise electronic speed control throughout substantially the entire range of the available speeds.
It is a further object of the present invention to provide an internal combustion engine that is compact, lightweight and efficient in operation.
It is a still further object of the present invention to provide an internal combustion engine that is economical in manufacture and operation.